Letters patent were letters issued open or 'patent' expressing the sovereign's will on a variety of matters of public interest, sealed with the sovereign's great seal pendent. The patent rolls record the issue of letters patent from the reign of King John until the present day. There are gaps in the series where some rolls have been lost. For example, the rolls for 23 and 24 Henry III are known already to have been lost by 1381.

Entries on the rolls are of a very diverse nature, referring to the royal prerogative, revenue, the different branches of the judicature, treaties, truces, correspondence and negotiations with foreign princes and states, letters of protection, of credence and of safe-conduct, and the appointments and powers of ambassadors.

There are also grants and confirmations of liberties, offices, privileges, lands and wardships, both to public bodies and to private individuals; charters of incorporation; licences for the election of bishops and other ecclesiastics; restitutions of temporalities; presentations to livings; creations of nobility and baronetcy; special and general pardons; special liveries; licences and pardons for alienation; Crown leases; and licences in mortmain. After 1516 grants of the kind previously made by royal charters were made by letters patent.

Between 1645 and Charles II's accession in 1660 there are only six patent rolls. It is probable that the letters patent issued in the unrepresented years were never enrolled. Letters patent were much reduced in the course of the nineteenth and twentieth centuries, as the kind of instruments produced thereby became obsolete or their administration passed to other bodies. The use of the great seal was much restricted, and often replaced by alternative devices.

From 1702 the contents of the rolls are mostly grants of offices and pensions, creations of nobility, and letters patent of inventions and denization. There are also some early commissions of bankruptcy. Letters of denization were entered on the patent rolls until 1844, when responsibility passed to the Home Office although a few appear subsequently.

Before, and after, the existence of the Court of Wards and Liveries, grants for the custody of the persons and estates of idiots and lunatics were enrolled on the patent rolls. Letters patent for inventions were also enrolled there until 1853. After that date they were administered by a separate Patent Office. The inventions had accounted for the bulk of letters patent, and their removal reduced the rolls to three to five per year instead of thirty.

Commissions of all kinds may be found on the dorse of the rolls, including commissions of array, of musters, of lords lieutenant of counties, of justices of the peace, of oyer and terminer, and of sewers, as well as special commissions of various kinds. The practice of enrolling the commissions of the peace, of oyer and terminer, of sewers and of gaol delivery was spasmodic from the 1530s, discontinued after 1564, and not resumed until 1594. They finally cease to appear about 1665. Proclamations are entered on the dorse of patent rolls until 1896; thereafter they appear on the last patent roll for each year.